SHAPE MEASURING METHOD AND DEVICE

摘要

PROBLEM TO BE SOLVED: To measure shapes highly accurately by obtaining an interference phase value based on an optical path difference from a group of interference fringe intensity distributions obtained for every phase shift value, and obtaining a wavelength phase ratio from the amount of phase difference between the interference phase value of a scanning wavelength and interference phase value of a center wavelength, and the amount of wavelength shift. SOLUTION: A light beam emergent from a light source 1 is linearly polarized and becomes incident onto a Michelson interferometer 3 and separated into irradiation light 6 and reference light 7 by a beam splitter 5 at the interferometer 3. The irradiation light 6 is reflected at an object to be measured 8 to generate object light 10. The reference light 7 becomes incident onto a PZT mirror 9 which functions as a phase shifter. The reference light 7 and object light 10 reflected at a PZT mirror 9 are photoelectrically detected by a CCD camera 12. Then a computer 13 controls the wavelength scanning of the light source 1 and micro displacements of the mirror 9 and obtains a wavelength phase ratio from the amount of phase difference between the interference phase value of a scanning wavelength and interference phase value of a center wavelength, and the amount of wavelength shift to measure the shape of the object to be measured 8.